Waymo, the former Google self-driving project that spun out to become a business under Alphabet, is launching a program in Phoenix next month that will focus on delivering people to bus stops and train and light-rail stations.

The pilot program announced Tuesday is in partnership with Valley Metro, the Phoenix area’s regional public transportation authority.

The announcement gives clarity to the fourth leg in Waymo’s business strategy. The company’s has publicly shared plans to focus on four areas: create a ride-hailing service, develop self-driving trucks for logistics and license its technology to automakers for personally owned vehicles.

But it was the fourth piece — connecting people to public transportation — that was nebulous until now.

The program initially will be offered to employees of Valley Metro. These riders will be able to use the Waymo app to hail a ride in one of the company’s autonomous Chrysler Pacifica Hybrid minivans to take them to the nearest public transportation option.

Waymo will expand the program and provide first-and-last mile travel to Valley Metro RideChoice travelers, which covers groups traditionally underserved by public transit.

Waymo and Valley Metro hope to learn more about how people use public transit and what role self-driving cars can have in connecting people to the buses, trains and light-rail systems found in cities.

The company said it hopes to open the service to the public in the future.

Phoenix has become a major testing hub for Waymo. The company has been testing its self-driving vehicles there for months and launched an early rider program. In March, Waymo began shuttling a group of early riders in self-driving vehicles without a human test driver behind the wheel.

Last week, the company, announced a series of partnerships with Walmart, AutoNation, Avis and others to give customers access to autonomous vehicles. Under the partnerships, Waymo will pick up customers and drive them to businesses in the Phoenix area.